Process of refrigeration.



A. W. BROWNE & R. P. NICHOLS.

PROCESS OF REFRIGERATION. APPLICATION FILED DEC-3.1912.

Patented Nov. 20, 1917.

UNITED STATES PATENT oEEIoE.

ARTHUR W. BROWNE, OF ITHACA, NEW YORK, AND ROBERT P. NICHOLS, OI PHILA-DELPHIA, BENNSYLVANIA.

PROCESS OF REFRIGERATION.

To all whom it may concern: I

Be it known that we, ARTHUR W. BROWNE,

a citizen of the United States, and resident of Ithaca, county ofTompkins, State of New York, and ROBERT P. NIcHoLs, a citi zen of theUnited States, and resident of Philadelphia, county of Phiiadelphia,State of a process of refrigeration by the absorption of a gas, such asammonia, from the refrigerating pipes arranged in the zone ofrefrigeration. It is well known that water has been used in this manneras the absorber for the ammonia gas. It has also been proposed to usecertain chemical salts, such as ammonium thiocyanate and ammoniumnitrate, which are readily soluble in the ammonia which they absorb, andthe use of calcium chlorid as an absorbent has also been suggested.

When water is used as the absorber without a pump it has been foundextremely diliicult, if not impossible, to prevent the distillation ofpart of the water with the ammonia gas on heating the ammonium hydroxid.To prevent this a reflux or dephlegmator must be used, but even thenmore or less Water eventually accumulates in the refrigerating coils,retarding, and sometimes stopping, the reabsorption of the ammonia.

WVhen chemical salts are used that are very soluble in ammonia, theyform a liquid when they absorb the ammonia gas, and in this there areseveral disadvantages. The chief of these is that when heat is appliedto drive off the ammonia gas, there is considerable decomposition of thesalt itself. Some of the products of this decomposition are volatile andare distilled into the refrigerating coils and there condensed. This hasa tendency to retard the evaporation of the liquid ammonia from thecoils and also reduces the power of the salt as an absorbing agent. Thedecomposition may moreover in certain cases result in the production ofdangerously high pressures, and even of explosive gas mixtures. It iswell known, for example, that nitrous oxid may be formed by the heatingof ammonium nitrate, andthat mixtures of nitrous oXid and ammoniaexplode violently under certain conditions. There are still otherobjections to the use of liquids as Specification of Letters Patent.

'forms a white substance (CuSOQ.

Patented Nov. 20, 1917.

Application filed December 3, 1912. Serial No. 734,672.

absorbers, such as the necessity o using agitating or bubbling devicesto promote the absorption of the ammonia gas on its return to theabsorber, and the difliculty of shipment without spilling liquid intothe refrigerating coils.

It is the object of our invention to overcome these objections toabsorption methods of refrigeration, and this we accomplish by the useof anhydrous copper sulfate as a type of solid absorber, capable ofabsorbing the ammonia gas, without liquefaction and withoutdecomposition at the temperatures normally used in a refrigeratingprocess of this kind.

By solid absorbers are meant absorbers which are practically anhydrous,as the presence of moisture in appreciable quantity will render theammonate more or less subect to liquefaction or decomposition andincapable of acting efiiciently in a refrigeratmg process.

In carrying out our process the solid absorber with its contents ofabsorbed refrigerant is placed in a suitable chamber adapted to bealternately heated and cooled. When the absorber is heated therefrigerating agent is given off in the form of a gas; this gas is thencondensed into a liquid, and the liquid passes into the refrigeratingcoils. This liquid is then evaporated in the refrigerating coils byrelieving the pressure in the system by cooling the absorber, and thegas thus produced passes back to and is reabsorbed by the absorber: Thisreconversion of the liquid into a gas in the refrigerating coils acts inthe well known manner to take up the heat from its surroundings and toproduce the desired refrigeration. I

We have found the ammonate of copper sulfate (CuSO,.5NH excellentlysuited to our process, and we claim this substance specifically. Thissubstance is obtained from the blue crystals of the salt (CuSO,.5H,O),which when dehydrated This substance (CuSO,) will absorb as manymolecules'of ammonia (NI-I as the original salt contained of Water,without liquefaction, so that we have the solid ammonate (CuSO,.5NH Whenthis is heated to the proper degree the ammonia is given off in the formof a gas and passes to the condenser where it IS liquefied. Thence itflows into the refrigerating coils, and when the pressure is reduced bythe cooling of the absorber (CuSQ it will return into gaseous .form andbe reabsorbed by the absorber, which'at all times remains in a solidform.

In the accompanying drawings we have shown diagrammatically an apparatusfor carrying out the process, with the valve chamber, the container forthe absorber, the condenser, and the refrigerating chamber in section. I

a is a container for the solid absorber with its absorbed refrigerant sin which is arranged a coil of pipe 6, supplied by a pipe Z) from thewater main 0, and discharging through a pipe d. Through this pipe I)water is supplied to the coil 6 from the main 0, under the control of avalve e.

From the container aa discharge pipe f leads to the condensing coils gin the condenser h, and these condensing coils communicate through apipe '5 with the refrigerating coils j in the refrigerating chamber is.

A pipe m leads from the water main 0 to the condenser and a dischargepipe n leads from the condenser to the discharge pipe d.

7 Suitable means are employed for alternately heating and cooling thematerial 8 in the container at. For the purpose of heating the materialwe have shown an electrical heater consisting of a resistance ribbon 0arranged about the coil and connected with the binding posts 0, 0 Thecooling is efiected by the passage of water through the coil when thevalve 6 is opened and the current through the heater 0 is cutofi'.

As shown the valve 6 is operated electrically through a lever econtrolled by the solenoids e ,-e and the lever is provided with aswitch p, p in the circuit 70 p which includes the heater 0.

In the apparatus shown the heating and cooling of the solid material sin the container a is controlled automatically by the conditions in therefrigerating coils j. For this purpose there is arranged in the coils ja vertical tube 25 having at the bottom and top a pair of electricalcontacts 16, t and 25* respectively. These are controlled by a metallicfloat u.

One winding of the solenoids e 6 is connected by the conductor m withthe one wire m of the main circuit. The other windings of the solenoidse 6 are connected by the wires 3 3 with the contacts t respectively. Thecontacts 6' and t are connected by the wire y with the return 3 Theoperation is as follows:

When the valve e and switch 7), p are closed current will pass throughthe heater a heating the material 8 and causing the ammonia or otherrefrigerating agent to separate from the absorber and pass in the formof a gas into the condenser It. Here the gas will be condensed by thecold water circulating through the pipes m, n, and the pressure createdwill flow in a liquid state through the pipe 2' into the refrigeratingcoils 9'. As the liquid accumulates in the refrigerating coils it willrise in the tube 25 and lift the float it until it closes the circuitthrough the contacts t t. This will immediately energize the othersolenoid and operate the lever e to open the valve 6 and the switch 39,12'. Current will then be cut off to the heater in the container a andcold water will flow through the coil 7;. This will immediately lowerthe temperature and pressure in the apparatus, with the result that theliquid in the refrigerating coils will be reconverted into gas andreabsorbed by the absorber in the container. lVhen the refrigerant isthus reconverted into gas and reabsorbed from the coils j the float uwill descend and close the circuit between the contacts t, F, thusenergizing the other solenoid, and closing the valve 6 and switch p, p.The material in the container a will then be again heated to give oifthe refrigerating gas and the operations described will be repeated.

To prevent any of the material in the container a passing in a solidform from the container, a porous screen to may be arranged over theoutlet to the pipe 7.

The apparatus which we Have shown will have more or less of anintermittent refrigerating action, but that will ordinarily besufficient, and where a continuous heat absorption is required in therefrigereating room or chamber, a plurality of such units may beemployed, set to act alternately or in succession.

WVhile we have shown an electrical heater in the container at forheating the material to liberate the refrigerant gas, and have alsoshown the apparatus under electrical control by the conditions in therefrigerating coils, our process is not limited to the use of suchmeans; and while we do not here claim the apparatus shown we reserve theright to patent the same in a separate application.

What we claim is as follows:

1. The method of refrigerating which comprises heating anhydrousammonate of copper sulfate within ranges of temperature and pressurelower than the fusion or decomposition point of the same, utilizing theresultant solid anhydrous copper sulfate as the absorbent and cyclicallyrepeating the aforesaid steps.

2. The method of refrigerating which comprises heating substantiallyanhydrous ammonate of copper sulfate within ranges of pressure andtemperature lower than the fusion or decomposition point of the same tothereby gasify ammonia therefrom, condensing the resulting ammonia inthe form of a substantially anhydrous liquid, leading the resultingsubstantially anhydrous ammonia through suitable refrigerating: pas- Intestimony of which invention, we heresages, withdrawing thesubstantially anhyunto set our hands.

drous ammonia from said refrigerating pas- ARTHUR W. BROWNE. sages inthe form of a substantially anh V- ROBERT P. NICHOLS.

5 drous gas under conditions of reduced pres- Witnesses as to Arthur lV.Browne:

sure and temperature to the resultant sub- JAs. R. ROBINSON, J12,stantially anhydrous solid copper sulfate to B. T. COOK. again form thesubstantially anhydrous \Vitnesses as to Robert P. Nichols: solidaminonate of copper sulfate, and cy- A. M. KELLY,

10 clically repeating the aforesaid steps. E. \V. SMITH;

